Help, something keeps messing up my network connection

This is the 2nd time it's happened. Randomly, Firefox and IE won't browse anywhere. Period. I can tell the hostname is resolving, but it won't connect. Oddly, some other network apps work.. I can ftp just fine, online chat, etc. Even more odd, if I open a DOS prompt and do "telnet www.google.com 80" then type "GET / HTTP/1.0", it works perfectly. What the hell?? Google Notify doesn't work though.. it can't check email. Weirdest thing: I can't even connect to my OWN ROUTER (192.168.0.1). Yet I can manually telnet to port 80 on any of these web sites.

I have NOD32, Comodo Firewall, and Spyware Terminator. I'm 90% sure one of these is causing this problem, as I didn't have this issue before I installed these. I turned off Comodo just now and it didn't resolve the issue. Actually I exited all three apps, still didn't fix the problem.

Oddly enough, if I turn on Tor, I can surf via that (Privoxy + Vidalia).

Addendum: it seems to be specifically related to the HTTP protocol.. NOT a specific port. I can't surf to port 8080 either. I know a reboot will fix all this, I'm just avoiding rebooting so I can possibly troubleshoot and figure out what's causing this.